Trade and transport

The Indus civilization's economy appears to have depended significantly on
trade, which was facilitated by major advances in transport technology. These
advances included bullock carts that are identical to those seen throughout
South Asia today, as well as boats. Most of these boats were probably small,
flat-bottomed craft, perhaps driven by sail, similar to those one can see on the
Indus River today; however, there is secondary evidence of sea-going craft.
Archaeologists have discovered a massive, dredged canal and docking facility at
the coastal city of Lothal.

During 4300 - 3200 BC of the chalcolithic period (copper age), the Indus Valley
Civilization area shows ceramic similarities with southern Turkmenistan and
northern Iran which suggest considerable mobility and trade. During the Early
Harappan period (about 3200–2600 BC), similarities in pottery, seals, figurines,
ornaments etc. document intensive caravan trade with Central Asia and the
Iranian plateau.

Judging from the dispersal of Indus civilisation artifacts, the trade networks,
economically, integrated a huge area, including portions of Afghanistan, the
coastal regions of Persia, northern and central India, and Mesopotamia.

There was an extensive maritime trade network operating between the Harappan and
Mesopotamian civilisations as early as the middle Harappan Phase, with much
commerce being handled by "middlemen merchants from Dilmun" (modern Bahrain and
Failaka located in the Persian Gulf). Such long-distance sea-trade became
feasible with the innovative development of plank-built watercraft, equipped
with a single central mast supporting a sail of woven rushes or cloth.

Several coastal settlements like Sotkagen-dor (astride Dasht River, north of
Jiwani), Sokhta Koh (astride Shadi River, north of Pasni) and Balakot (near
Sonmiani) in Pakistan along with Lothal in India testify to their role as
Harappan trading outposts. Shallow harbors located at the estuary of rivers
opening into the sea allowed brisk maritime trade with Mesopotamian cities.